Norwich - Norwich Public Utilities has received approval from the City Council for $5.9 million to cover three water system improvements that jumped to the top of the list of capital projects when federal stimulus grants and low-interest loans became available.

The three projects will be funded through water rates, requiring an estimated 5 percent rate increase for the three combined projects, NPU General Manager John Bilda said. The rate impact could be reduced if more than the expected 20 percent can be covered by grants to supplant the 2 percent loan expected to cover 80 percent of the project.

The projects include $1.83 million for a filter backwash recycle system at the Stonybrook Reservoir, $1.63 million to replace an aging water transmission line from the Deep River Reservoir in Lebanon and $2.44 million to replace the Deep River Reservoir pump and drive system and replace a large water storage tank in Norwich.

Bilda said the Deep River water line dates to 1924 and runs through a low-lying, flood-prone field in Lebanon. Bilda is concerned the joints in the pipe could become "compromised" and break if the high-pressure flow of water is disrupted for any reason. The line would be replaced with a new, 30-inch diameter water main that would run from the reservoir along Camp Moween Road in Lebanon.

The Deep River Reservoir pumps and motors are 40 years old and would be replaced.

Two smaller ground-based water storage tanks would replace the large tank in Mohegan Park in Norwich. The two new tanks would be built on land near the water treatment facility at the Deep Water Reservoir. The tanks, about 50 feet tall and 50 feet in diameter, would hold about 500,000 gallons each. They would replace the 5 million gallon tank at Mohegan Park. Bilda said because that current tank is so large, water sits and can become stagnant, leading to water quality issues. New technology would allow the water system to function efficiently with the two smaller tanks, he said.

The council unanimously approved bonding ordinances Monday for all three projects, with bonds to be paid for through water rates rather than taxes.

c.bessette@theday.com